Platen mechanism



1943- E. M. LIPPERT 2,318,000

PLATEN MECHAN I SM Filed March 14, 1941 5 Sheets- Sheet 1 E. M. LI'PPERT PLATEN MECHANISM May 4, 1943.

May 4,- 1943. E. LIPPERT PLATEN MECHANISM Filed March 14, 1941 s Sheets-Sheet 3 Er/Zar'fY Patented May 4, 1943 mates PLATEN MECHANISM Erhard M. Lippert, Chicago, Ill., assignor to Victor Adding Machine Company, Chicago, 11].,

a corporation of Illinois Application March 14, 1941, Serial No. 383,259

7 Claims.

This invention relates to improvements in platen mechanisms for printing machines, such for example as may be used in adding machines.

In printing machines, such for example, as adding machines, the plane at which the printing occurs is usually concealed from the view of the operator. Hence, if the paper, whether a strip from a roll or an independent sheet, is to be printed in closely spaced successive lines, the usual single line space advance of the paper after each printing may not raise the printed line to a position where it may be viewed by the operator. While a large amount of movement of the platen support after each printing might place the printed line in view, yet such large movement is sometimes not practical or desirable. To overcome this difficulty without extensive movement of the platen support, this invention provides for advancing the paper an unusually great distance on the platen support after each printing, and reversing it again in preparation for the next printing, when it is desired to closely space the successive printed lines. This objective can be accomplished either with a rotating platen support or some other form of platen support, for example a reciprocating platen support.

When the foregoing described improvement is embodied in an adding machine having a rockable platen support, a number of desirable advantages are gained. For example, since the paper is moved on its platen support, the platen frame need not rock back from the printing plane as far as might otherwise be necessary. Consequently, the overall space occupied by the movements of the platen frame are minimized and it becomes practical to house the platen mechanism within a compact housing of minimum dimensions.

The manner of incorporating these new advantages in a rockable platen mechanism for use with a printing machine, particularly an adding machine, is described and illustrated herein. However, it will be perceived that the broader objectives of this invention may be achieved by incorporation into platen mechanisms other than rockable platen mechanisms.

One of the objects of this invention is to provide a platen mechanism which will, after each printing, advance the paper to raise the printed line up to a plane of visibility and reverse the paper feed before the next printing operation to cause the next line to be printed in desired close consecutive order. I

Another object of the invention is to provide a platen mechanism having the foregoing features but with the added feature of not reversing the feed after a total is printed and advanced to the line of visibility, for the purpose of leaving a blank spaceof considerable width between the printed total and the next succeeding line of printed matter.

.Another object of the invention is to provide the foregoing features in a rockable platen mechanism wherein a platen roll carrying the paper is pressed against the printing type.

Another object of the invention is to provide any or all of the foregoing features in a rockable platen mechanism to thereby reduce to a minimum the extent of its rocking movement whereby the overall space occupied by the platen mechanism may be'reduced to a minimum.

Other objects and advantages of the invention will be mentioned specifically hereinafter or will lee-apparent from a perusal of the following specification, wherein a preferred embodiment of the invention is described.

Fig. 1 of the drawings is a skeleton sideview of a platen mechanism made in accordance with this invention and showing the parts in thelposition occupied by them just as a total is being printed.

Fig. 2 shows, with greater detail; the next succeeding position of the platen mechanism following the position shown in Fig. 1 with the platen rocked back from the printing plane.

. Fig. 3 is an elevation of the platen assembly.

Fig. 4 is a sectional view on the line 4-4 of Fig. 3.

The platen mechanism herein illustrated and described, while capable of being modified or designed to be operated with other adding machines has been designed and proportioned for use with the machine shown in the co-pending application of Thomas O. Mehan, Serial No. 371,366, filed December 23, 1940, in which will be found the same operating shaft and platen rocker arms as well as the general frame construction shown in these.

drawings.

Referring further to the drawings, the frame of the machine includesa base plate I to which the several upstanding frame members may be connected by swedging, riveting or otherwise, the upstanding frame members necessary for the support of the platen mechanism' being indicated as 2, 3, and 4.

The platen frame includes two side plates 5 and 6 which are mounted on a shaft 1 having bushings 8 and 9 supported in the vertical frame plates '4 and 3 respectively."

The platen roller H is fixed on a shaft l2 rotatably supported in bushings carried by the platen side plates 5 and 6. As shown in Fig. 2, the machine with which this platen mechanism is employed will have a main operating shaft I3 on which is fixed a plate H to which is pivotally connected at |5, at the right-hand side of the machine, the rocking link l6. At the left-hand side of the machine is a corresponding plate and rocking link of identical shape, but not shown. Upon the rotation of the main operating shaft in the direction of the arrow, the resulting motion of the link l6 and its counterpart on the other side of the machine will cause the platen frame to rock in a counter-clockwise direction about the shaft 1, as viewed in Fig. 1, to swing the platen roll down to the printing plane.

The platen roller H has secured to it at its right end as seen in Fig. 3 a knurled wheel IT, by means of which the platen roller may be rotated manually in either direction. end there, is also secured to the platen roller a toothed wheel l8, against which is resiliently pressed a roller |9 carried on an arm 2| pivotally supported at 22 on the side plate 5 with a spring 23 anchored at 24 for resiliently holding the roller against the toothed wheel l8. The spacing of the teeth on the wheel I8 is such as to provide the appropriate line spacing between successive printed lines on the paper carried over the platen roll.

The shaft of the roller is supported in bushings 25 and 26 which are fixed on the platen side plates 5 and 6. Fixed on the right end of the platen roller shaft in any suitable manner are a pair of ratchet gears 21 and 28 having their teeth cut in opposing directions so that the outer gear 28 may. be used for advancingthe platen roller and the inner gear for reversing it. Pawls having teeth appropriately cut to accomplish these two effects are indicated as 29 and 3| and both are pivotally mounted on the rivet 32 supported on the bell crank 33, the latter beingrockably pivoted at the right end of the shaft 1. Springs 34 and 35 anchored on the post 36 carried on the platen side plate 6 are connected to the pawls 29 and 3| to normally urge their toothed ends toward the ratchet gears. In the position of rest the two pawls are held out of contact with their respective ratchet gears by their opposite ends 28'- and 21' which rest against an offset ear 31 which is formed on the bell crank 33.

To rock the platenframe, the machine is given a forward stroke whereupon the link l6 and its counterpart IE on the other side of the frame (not shown) will move rearwardly, and. during part of that motion, the slot such as 38 provided in the rear end of each link will slide along a post such as 39 extending from the side of the platen frame plate 6 until the forward end of the slot strikes the post, after which and during the remainder of the forward stroke of the machine the links will then cause the platen frame to rotate in a counter-clockwise direction a short distance, but sufficiently to press the platen roller against the type wheels.

As soon as the forward stroke commences, the post 4| carried at the rear end of the link l6 acting in the slot 42 of bell crank 33 will cause the rivet 32 carried on this bell crank to be swung in a counter-clockwise direction and since the two pawls are pivoted on that rivet, they will be moved bodily forwardly, the feeding pawl having no effect while the reversing pawl engages the teeth on the ratchet wheel 21 and re- At its left verses the platen roller a sufficient distance to carry the paper strip downwardly so that the last line previously printed and visible when the platen was at rest will now be positioned just above the level of the next line to be printed when the platen presses the paper against the type wheels. This is the normal operation of the machine when successive additions or subtractions are performed. As will be explained later, if the previous printing operation had happened to be the printing of a total, the reversing of the platen roller would not take place on the forward stroke.

Mounted rockably on the bushing 29 just out side the platen frame member 6 is a pawl release member 43 whose at rest position is shown in dotted lines in Fig. 2. As there shown, a laterally extending ear 44 on this member is connected with a spring 45 anchored at 46, which normally holds the stop projection 41 likewise provided on the member against the post 46. Also integral with the member 43 is an offset car 48 which acts as the reversing pawl release. The normal position of the latter ear is shown in dotted lines in Fig. 2.

Just below the offset ear on the pawl release is a shoulder 49 provided for locking the pawl release in the position shown in Fig. 2, as a result of the operation of the total key followed by a forward stroke. Cooperating with this locking shoulder 49 is a dog 5| pivoted on the rivet 52 supported on the platen side frame plate 6. This dog carries a post 53, best shown in Fig. 1, which is acted upon by the link 54 to cause the rotation of the locking dog. Link 54 in its normal at rest position occupies the position shown in Fig. 2. During the forward stroke of an adding operation when the total key 55 is in the neutral position shown in Fig. 2, the link 54 will not effect suflicient rotation of the locking dog to cause the reverse pawl releasing member to be locked up into the position shown in Fig. 2. This link is provided with a slot 56 through which extends a pivot post 5'! carried by the platen side frame plate 6. A washer 58 prevents the separation of these two parts. At the forward end of the link an open-ended slot 59 is held by spring 69 in engagement with the pin 6| which extends laterally from one side of the total key.

If the total key be rotated about its axis 62 so that the handle 63 moves rearwardly, that is to the sub-total position for the machine, the forward end of the link engaged with the pin 6| will be slightly lifted, and when the platen carriage frame is swung downwardly during the forward stroke of the machine the post 53 on the locking dog 5| will engage the lower edge of the link 54 and be rotated in a clockwise direction against the action of its spring 64 a sufficient distance to rise above the shoulder 49 just beneath the pawl release ear 48, and on the return stroke the dog will hold the member 43 locked out of normal, as shown in Fig. 2.

Should the total key have been rotated forwardly to the total-taking position for this machine, the link would be thrust rearwardly, the slot 56 riding along the pin 51, but the same cooperation of the link and the pin 53 would occur causing the locking dog to be rotated to the position shown in Fig. 1 at the end of the forward stroke and to be held up by the locking shoulder 49 at the end of the return stroke as shown in Fig. 2.

Whether the pawl release member 43 be locked in the position shown in Fig. 2 by the sub-total or total operation of the key, in either event during the next succeeding forward stroke, the reversing pawl 29 will be prevented from engaging the reversing ratchet. Hence, the paper on the platen roll will not move during the forward and downward swinging of the platen roller. Consequently, the numbers printed following the printing of a total will be spaced considerably below the printed total, (four lines below in the illustrated machine), permitting the strip of paper carrying the preceding total to be torn off and leaving a margin above the next sums to contain a memorandum, if one desires to write one on the paper. torn off at this time, manual rotation of the platen roll is not necessary to provide a space between a printed total and the next series of added figures. If after a total-printing operation the strip of paper was torn off and the platen was permitted to reverse on the succeeding adding operation, the figures would be printed too close to the top of the strip, but by preventing the reversal of the platen on this operation, the next printed line will have an ample blank space above it.

To release the member 43 from the locked position shown in Fig. 2 there is provided a member 65 pivoted on the rivet 32 embracing or straddling the reversing pawl 21 and having a forwardly projecting nose 66 which is so positioned that if the release member 43 be looked as shown in Fig. 2 and the total key is either in neutral or sub-total position during the forward stroke, the nose 66, being carried forwardly on the bell crank 33 through its mounting on the rivet 32, will engage the car 48 and rotate it counter-clockwise sufficiently to release the locking dog before the link 54 contacts the post 53. Subsequently, when the link 54 rotates the locking dog, not only is the locking dog released but the nose 66 rotates release member 43 so far during the forward stroke that even though the'total key be in subtotal position, the rotation of the locking dog which results therefrom by the action of the link 54 will not be suilicient to overtake the locking shoulder 49.

However, if a total operation is performed, thus locking the member 43 as shown in Fig. 2, and is followed by another total operation, the member 43 will not be unlocked on the forward stroke of the second total operation, by reason of the following provision. The member 65 is also provided with an ear 61 which extends laterally therefrom to the left across the top of the edge portion 68 of the link 54. Hence, any time the total key is operated to total position and the link 54 is thereby moved rearwardly, this edge portion of the link will lift against the projection 61 to swing the nose 66 high enough so that as the nose 66 moves forwardly with reference to the ear 48, it will not engage the latter but rather will pass above it. Hence, the interlock of the shoulder 49 and dog 5| will not be disturbed. To hold the member 65 resiliently downwardly, an ear 69 is provided thereon extending downwardly between the pawls 21 and 28 and having attached thereto a spring 'H anchored at 12 at the top of the vertical frame plate 2.

Briefly, therefore, the platen roller will be reversed during the forward stroke on successive adding or subtracting operations. It will reverse during the forward stroke of a total or sub-total operation, but will not reverse on the forward stroke succeeding either of those total operations. After either total operation the next succeeding Whether or not the strip is rest position engages a post 15 extending laterally from the platen side frame plate 6, as shown in Fig. 2. The spring 16 connected'to'the lower end of this hook member and to'the lower end of the platen frame member 6 urges the hook into such engagement. In the adding machine to which this mechanism is designed to be attached there is a rack restore bail rod 11, as describedin the aforesaid application Serial No. 371,366, filed by Thomas O. Mehan on December 23, 1940. During the forward stroke of the machine, this bail rod moves upwardly through the curved slot 18 and near the end of the forward stroke, the end of the rod' 11 strikes the projection 19 extending forwardly from the hook member 12 and kicks that member rearwardly thus disengaging the hook from the post 15 in time to thus release the platen frame and permit the rocking link "5 to swing the platen roller downwardly against the type wheels. During the return stroke when the platen frame swings upwardly again, the hook 14 will re-engage the post 15' and holdthe platen frame firmly in its normal at rest position.

The guiding and feeding of the paper is provided for as follows: The paper roll, not'shown, is rotatably supported at the rear of the machine in any suitable manner, for example, between a pair of p ates, one ofwhich designated! is shown in Fig. 2 and is carried up along the rear surface of the plate 82 and is fed thence between the platen roller H and a knurled roller 83 which is carried between a pair of bail arms 84 and 85 pivotally. mounted on an axis at 86, the knurled roller being held resiliently against the platen roller by means of the spring 81 connected to an arm 88 depending from one of the bail arms. The

' paper is then fed underneath the platen roller and is guided by a plurality of'fingers 89 and 9| which are formed. integrally with a plate 9Z'whose' ends are bent and shaped to form apivotal support for theassembly on the axis 85. The forward ends of these fingers are restrained inside of a-tear strip 93 having a serrated edge 94, the paper then passing up intoview around the platen roller. The printing plane for the machine is located at the position of the ribbon 95, the type of the printing wheels (not shown) extending between the teeth 96 of a comb. At opposite ends ofthe printing position, that is outside of the type wheels, are located a pair of abutments, oneof which is shown in Fig. 2 and is designated 91, which are struck by the finger 9| as the platen roller swings into printing position, causing all of the fingers on the associated rotatable plate to be pressed firmly against the paper on the platen roll to hold the same immovable during the printing operation.

The platen mechanism herein shown obviously has only a very short oscillatory movement. Consequently, it is practical to house it completely within a casing for the adding machine which will thereforeserve to protect the machine better from dust, and at the same time providea neater appearance to the device. While the casing is not a part of my invention, certain advantages of my invention will be better appreciated by illustrating how compactly it may be housed 

